The primary objective of the National Surgical Adjuvant Project for Breast and Bowel (NSABP) are to produce reliable, statistically significant data relative to the natural history and treatment of breast and, more recently, bowel cancers. The method employed in the fulfillment of these objectives is that of well-designed, sequential protocols applied to the large patient population generated by the seventy-four (74) member institutions. As a participating institution, the University of Iowa has contributed to patient accural in Protocols #B-04, #B-07, #B-09, and #B-10. Quality follow-up has been maintained on all patients randomized to these protocols. Our multidisciplinary approach and strict compliance with protocol requirements enhance the overall group objectives. Our eight years of experience with the clinical trials of this cooperative group, coupled with a recent reorganization designed to yield increased patient accrual provide the framework for a major contribution to future NSABP endeavors. The present application seeks funding to permit: (1) Continued patient accrual in ongoing protocols; (2) Prolonged follow-up on all protocol patients; (3) Collection of appropriate biological materials and information relevant to these protocols; (4) Education through dissemination of information and participation in cooperative clinical trials by community physicians.